function SuperType(str) {
  this.str = str ?? "none";
  this.arr = [1, 2, 3];
  this.fn = () => console.log(1);
}
const superType = new SuperType("superType");
console.log(superType);

function createSubType(obj) {
  const clone = clone(obj);
  clone.num = 123;
  return clone;
}

/**
 * 优点：
 * 缺点：
 */

const subType = createSubType(new SuperType());
console.log(subType);
